Effect of shock wave-facilitated intracoronary cell therapy on LVEF in patients with chronic heart failure: the CELLWAVE randomized clinical trial

IMPORTANCE

The modest effects of clinical studies using intracoronary administration of autologous bone marrow-derived mononuclear cells (BMCs) in patients with chronic postinfarction heart failure may be attributed to impaired homing of BMCs to the target area. Extracorporeal shock wave treatment has been experimentally shown to increase homing factors in the target tissue, resulting in enhanced retention of applied BMCs.

OBJECTIVE

To test the hypothesis that targeted cardiac shock wave pretreatment with subsequent application of BMCs improves recovery of left ventricular ejection fraction (LVEF) in patients with chronic heart failure.

DESIGN, SETTING, AND PARTICIPANTS

The CELLWAVE double-blind, randomized, placebo-controlled trial conducted among patients with chronic heart failure treated at Goethe University Frankfurt, Germany, between 2006 and 2011.

INTERVENTIONS

Single-blind low-dose (n = 42), high-dose (n = 40), or placebo (n = 21) shock wave pretreatment targeted to the left ventricular anterior wall. Twenty-four hours later, patients receiving shock wave pretreatment were randomized to receive double-blind intracoronary infusion of BMCs or placebo, and patients receiving placebo shock wave received intracoronary infusion of BMCs.

MAIN OUTCOMES AND MEASURES

Primary end point was change in LVEF from baseline to 4 months in the pooled groups shock wave + placebo infusion vs shock wave + BMCs; secondary end points included regional left ventricular function assessed by magnetic resonance imaging and clinical events.

RESULTS

The primary end point was significantly improved in the shock wave + BMCs group (absolute change in LVEF, 3.2% [95% CI, 2.0% to 4.4%]), compared with the shock wave + placebo infusion group (1.0% [95% CI, -0.3% to 2.2%]) (P = .02). Regional wall thickening improved significantly in the shock wave + BMCs group (3.6% [95% CI, 2.0% to 5.2%]) but not in the shock wave + placebo infusion group (0.5% [95% CI, -1.2% to 2.1%]) (P = .01). Overall occurrence of major adverse cardiac events was significantly less frequent in the shock wave + BMCs group (n = 32 events) compared with the placebo shock wave + BMCs (n = 18) and shock wave + placebo infusion (n = 61) groups (hazard ratio, 0.58 [95% CI, 0.40-0.85]; P = .02).

CONCLUSIONS AND RELEVANCE

Among patients with postinfarction chronic heart failure, shock wave-facilitated intracoronary administration of BMCs vs shock wave treatment alone resulted in a significant, albeit modest, improvement in LVEF at 4 months. Determining whether the increase in contractile function will translate into improved clinical outcomes requires confirmation in larger clinical end point trials.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00326989.

Intraarterial administration of bone marrow mononuclear cells in patients with critical limb ischemia: a randomized-start, placebo-controlled pilot trial (PROVASA)

BACKGROUND

Critical limb ischemia due to peripheral arterial occlusive disease is associated with a severely increased morbidity and mortality. There is no effective pharmacological therapy available. Injection of autologous bone marrow-derived mononuclear cells (BM-MNC) is a promising therapeutic option in patients with critical limb ischemia, but double-blind, randomized trials are lacking.

METHODS AND RESULTS

Forty patients with critical limb ischemia were included in a multicenter, phase II, double-blind, randomized-start trial to receive either intraarterial administration of BM-MNC or placebo followed by active treatment with BM-MNC (open label) after 3 months. Intraarterial administration of BM-MNC did not significantly increase ankle-brachial index and, thus, the trial missed its primary end point. However, cell therapy was associated with significantly improved ulcer healing (ulcer area, 3.2±4.7 cm(2) to 1.89±3.5 cm(2) [P=0.014] versus placebo, 2.92±3.5 cm(2) to 2.89±4.1 cm(2) [P=0.5]) and reduced rest pain (5.2±1.8 to 2.2±1.3 [P=0.009] versus placebo, 4.5±2.4 to 3.9±2.6 [P=0.3]) within 3 months. Limb salvage and amputation-free survival rates did not differ between the groups. Repeated BM-MNC administration and higher BM-MNC numbers and functionality were the only independent predictors of improved ulcer healing. Ulcer healing induced by repeated BM-MNC administration significantly correlated with limb salvage (r=0.8; P<0.001).

CONCLUSIONS

Intraarterial administration of BM-MNC is safe and feasible and accelerates wound healing in patients without extensive gangrene and impending amputation. These exploratory findings of this pilot trial need to be confirmed in a larger randomized trial in patients with critical limb ischemia and stable ulcers.

Sphingosine-1-Phosphate Stimulates the Functional Capacity of Progenitor Cells by Activation of the CXCR 4 -Dependent Signaling Pathway via the S1P 3 Receptor

Objective— Sphingosine-1-phosphate (S1P) is a bioactive lipid, which influences migration and proliferation of endothelial cells through activation of S1P receptors and has been shown to support SDF-1 induced migration and bone marrow homing of CD34 + progenitors.

Methods and Results— Here, we show that incubation of patient-derived endothelial progenitor cells (EPCs) with S1P or its synthetic analog FTY720 improved blood flow recovery in ischemic hind limbs. Likewise, recovery of blood flow was dramatically reduced after induction of hindlimb ischemia in mice deficient for the S1P receptor 3 (S1P 3 ). S1P 3 −/− bone marrow–derived mononuclear cells (BMCs) failed to augment neovascularization after hind limb ischemia. Of note, treatment of BMCs derived from S1P 3 −/− mice with S1P did not rescue blood flow recovery. Mechanistically, S1P and FTY720 induced phosphorylation of CXCR 4 , activated the Src kinase, and stimulated phosphorylation of JAK2. The contribution of CXCR 4 for S1P-mediated effects was further supported by the findings that S1P preincubation failed to stimulate invasion capacity and in vivo blood flow recovery of BMCs from CXCR 4 +/− mice. The activation of CXCR 4 was dependent on the Src kinase family as demonstrated by preincubation with the Src inhibitor PP2. The activation of the CXCR 4 signaling by S1P is mediated via the S1P 3 receptor, since S1P-induced Src phosphorylation was abrogated in EPC from S1P 3 −/− mice.

Conclusions— S1P agonists might serve as sensitizers of CXCR 4 -mediated signaling and may be applied in clinical progenitor cell therapy to improve EPC or BMC function in patients with coronary artery disease.

Therapeutic Angiogenesis Inhibits or Rescues Chemotherapy-induced Peripheral Neuropathy: Taxol- and Thalidomide-induced Injury of Vasa Nervorum is Ameliorated by VEGF

Toxic neuropathy represents an important clinical problem in the use of the chemotherapeutic substances Taxol and thalidomide. Sensory neuropathy has a high incidence, lacks an effective treatment and is the dose-limiting factor for these drugs. The pathogenic basis of these neuropathies is unknown. We investigated the hypothesis that the experimental toxic neuropathies from Taxol and thalidomide results from destruction of vasa nervorum and can be reversed by the administration of an angiogenic cytokine. In animal models of Taxol- and thalidomide-induced neuropathy, nerve blood flow has been attenuated and the number of vasa nervorum has been reduced. Intramuscular gene transfer of naked plasmid DNA encoding VEGF-1 administered in parallel with Taxol injections completely inhibited deterioration of nerve function and diminution of the peripheral nerve vasculature. Gene therapy in animals with established Taxol- or thalidomide-induced neuropathies resulted in recovery of vascularity and improved nerve electrophysiology. These findings implicate microvascular damage as the basis for toxic neuropathy and suggest that angiogenic growth factors may constitute a novel treatment for this disorder.

Effects of Granulocyte Colony Stimulating Factor on Functional Activities of Endothelial Progenitor Cells in Patients With Chronic Ischemic Heart Disease

OBJECTIVE

Bone marrow-derived circulating endothelial progenitor cells (EPCs) may contribute to regeneration of infarcted myocardium and enhance neovascularization. Granulocyte colony-stimulating factor (G-CSF) is well-established to mobilize hematopoietic stem cells (HSCs) and might, thereby, also increase the pool of endogenously circulating EPC. Therefore, we investigated the effects of G-CSF administration on mobilization and functional activities of blood-derived EPC in patients with chronic ischemic heart disease (CIHD).

METHODS AND RESULTS

Sixteen patients with CIHD received 10 microg/kg per day subcutaneous G-CSF injection for 5 days. Leukocyte counts, the number of HSCs and EPCs, and the migratory response to VEGF and SDF-1 were analyzed before and after G-CSF-therapy. At day 5 of G-CSF treatment, the number of circulating leukocytes, CD34+ CD45+ and CD34+ CD133+ cells was significantly increased. Likewise, G-CSF treatment augmented the numbers of colony forming units with endothelial cell morphology (EC-CFU). However, the functional activity of the EPC as assessed by the migratory response to VEGF and SDF-1 was significantly reduced after G-CSF treatment (P<0.01). Because G-CSF was previously shown to cleave the CXCR4 receptor, we determined the surface expression of the 6H8 epitope of the CXCR4 receptor by fluorescence-activated cell sorter (FACS) analysis. Consistent with the reduced migratory capacity, the surface expression of the functionally active CXCR4 receptor was significantly reduced. To test the functional activity of the cultivated EPCs in vivo, cells were intravenously infused in nude mice after hind limb ischemia. EPCs, which were cultivated before G-CSF administration, increased blood flow recovery and prevented limb necrosis. However, infusion of EPCs, which were isolated 5 days after G-CSF treatment from the same patient, showed a reduced capacity to augment blood flow recovery and to prevent necrosis by 27%.

CONCLUSIONS

G-CSF treatment effectively mobilizes HSCs and EPCs. However, the migratory response to SDF-1 and in vivo capacity of G-CSF-mobilized EPCs was significantly reduced.

Intracoronary infusion of progenitor cells is not associated with aggravated restenosis development or atherosclerotic disease progression in patients with acute myocardial infarction

AIMS

Experimental and clinical pilot studies suggest that intracoronary progenitor cell infusion can improve left ventricular function and remodelling after acute myocardial infarction (AMI). Since progenitor cells are also known to be involved in restenosis development and atherosclerosis progression, an increased restenosis rate may be a risk of intracoronary cell therapy.

METHODS

We performed a retrospective study to compare quantitative angiographic measurements of the infarct target vessel in 83 patients with AMI treated with bare metal stent PCI (matched control) and in 83 patients receiving additional intracoronary progenitor cell infusion at a mean of 5 days post-AMI stent PCI and after 4 months.

RESULTS

The late loss as a measure of neointima formation was similar between the control and the cell-treated group at follow-up (0.9+/-0.8 vs. 0.9+/-0.7 mm, P=0.9). Moreover, restenosis rate was comparable in both groups (35% control vs. 27% cell-treated group, P=0.2). Multivariable analysis excluded cell therapy as an independent significant predictor of increased late loss (P=0.4), whereas acute gain (P=0.012) and diabetes mellitus (P=0.002) were independent predictors of late loss. Finally, in the cell-treated group, target vessel revascularization rate remained at 28.9% during a median of >3 years of follow-up, thus excluding an effect on atherosclerotic disease progression.

CONCLUSION

In patients with AMI successfully treated with bare metal stent PCI, additional intracoronary progenitor cell infusion does not lead to an increased neointima formation within the implanted stent within 4 months or aggravation of atherosclerotic disease progression.

Impaired CXCR4 signaling contributes to the reduced neovascularization capacity of endothelial progenitor cells from patients with coronary artery disease

Transplantation of bone marrow cells as well as circulating endothelial progenitor cells (EPC) enhances neovascularization after ischemia. The chemokine receptor CXCR4 is essential for migration and homing of hematopoietic stem cells. Therefore, we investigated the role of CXCR4 and its downstream signaling cascade for the angiogenic capacity of cultured human EPC. Ex vivo, differentiated EPC derived from peripheral blood abundantly expressed CXCR4. Incubation of EPC from healthy volunteers with neutralizing antibodies against CXCR4 profoundly inhibited vascular endothelial growth factor- and stromal-derived factor-1-induced migration as well as EPC-induced angiogenesis in an ex vivo assay. Preincubation of transplanted EPC with CXCR4 antibody reduced EPC incorporation and impaired blood-flow recovery in ischemic hindlimbs of nude mice (57+/-4% of normal perfusion versus untreated EPC: 80+/-11%, P<0.001). Bone marrow mononuclear cells (BM-MNC) or EPC of heterozygous CXCR4(+/-) mice displayed reduced CXCR4 expression and disclosed impaired in vivo capacity to enhance recovery of ischemic blood flow in nude mice (blood flow 27+/-11% versus 66+/-25% using wild-type cells, P<0.01). Importantly, impaired blood flow in ischemic CXCR4(+/-) mice was rescued by injection of wild-type BM-MNC. Next, we investigated the role of CXCR4 for functional capacities of EPC from patients with coronary artery disease (CAD). Surface expression of CXCR4 was similar in EPC from patients with CAD compared with healthy controls. However, basal Janus kinase (JAK)-2 phosphorylation was significantly reduced and less responsive to stromal-derived factor-1 in EPC from patients with CAD compared with healthy volunteers, indicating that CXCR4-mediated JAK-2 signaling is dysregulated in EPC from patients with CAD. The CXCR4 receptor signaling profoundly modulates the angiogenic activity and homing capacity of cultured human EPC. Disturbance of CXCR4 signaling, as demonstrated by reduced JAK-2 phosphorylation, may contribute to functional impairment of EPC from patients with CAD. Stimulating CXCR4 signaling might improve functional properties of EPC and may rescue impaired neovascularization capacity of EPC derived from patients with CAD.

p38 mitogen-activated protein kinase downregulates endothelial progenitor cells

BACKGROUND

Transplantation of endothelial progenitor cells (EPCs) improves neovascularization after ischemia, but patients with coronary artery disease (CAD) or diabetes mellitus show a reduced number of EPCs and impaired functional activity. Therefore, we investigated the effects of risk factors, such as glucose and TNF-alpha, on the number of EPCs in vitro to elucidate the underlying mechanisms.

METHODS AND RESULTS

EPCs of patients or healthy subjects were isolated from peripheral blood. Incubation with glucose or TNF-alpha dose-dependently reduced the number of EPCs (79.9+/-1.3% and 74.3+/-8.1% of control; P<0.05, respectively). This reduction was not caused by apoptosis. TNF-alpha and glucose induced a dose- and time-dependent activation of the p38 MAP kinase, the downstream kinase mitogen- and stress-activated kinase 1, and the transcription factor cAMP-responsive element-binding protein (CREB), in EPCs. Moreover, EPCs from CAD patients had significantly higher basal p38-phosphorylation levels (1.83+/-0.2-fold increase; P<0.05) compared with healthy subjects. The inhibition of the p38-kinase by SB203580 or infection with a dominant negative p38 kinase adenovirus significantly increased basal number of EPCs (136.7+/-6.3% and 142.9+/-18% versus control, respectively). Likewise, ex vivo cultivation of EPCs from patients with CAD with SB203580 significantly increased the number of EPCs and partially reversed the impaired capacity for neovascularization of EPCs in vivo (relative blood flow: 0.40+/-0.03 versus 0.64+/-0.08, P<0.05). The increased numbers of EPCs by SB203580 were associated with an augmentation of EPC proliferation and a reduction of cells expressing the monocytic marker proteins CD14 and CD64, suggesting that p38 regulates proliferation and differentiation events.

CONCLUSIONS

These results demonstrate that p38 MAP kinase plays a pivotal role in the signal transduction pathways regulating the number of EPCs ex vivo. SB203580 can prevent the negative effects of TNF-alpha and glucose on the number of EPCs and may be useful to improve the number of EPCs for potential cell therapy.

Antiangiogenesis mediates cisplatin-induced peripheral neuropathy: attenuation or reversal by local vascular endothelial growth factor gene therapy without augmenting tumor growth

BACKGROUND

Toxic neuropathies induced by cisplatin and other chemotherapeutic agents are important clinical problems because of their high incidence, their lack of effective treatment, and the fact that neuropathy represents a dose-limiting factor for these therapies. The pathogenic basis for toxic neuropathies induced by chemotherapeutic agents has not been completely elucidated.

METHODS AND RESULTS

We investigated the hypothesis that experimental toxic neuropathy results from an antiangiogenic effect of these drugs, resulting in destruction of the vasa nervorum, and accordingly that the neuropathy could be prevented or reversed by locally administered VEGF gene transfer without augmenting tumor growth. In an animal model of cisplatin-induced neuropathy, nerve blood flow was markedly attenuated, and there was a profound reduction in the number of vasa nervorum associated with marked endothelial cell apoptosis, resulting in a severe peripheral neuropathy with focal axonal degeneration characteristic of ischemic neuropathy. After intramuscular gene transfer of naked plasmid DNA encoding VEGF-1 in animals with an established neuropathy, vascularity and blood flow returned to levels similar to those of control rats, peripheral nerve function was restored, and histological nerve architecture was normalized. Gene therapy administered in parallel with cisplatin chemotherapy completely attenuated endothelial cell apoptosis and inhibited destruction of nerve vasculature, deterioration of nerve function, and axonal degeneration. In a rat tumor model, VEGF gene transfer administered locally did not alter tumor growth or vascularity.

CONCLUSIONS

These findings implicate microvascular damage as the basis for toxic neuropathy induced by cisplatin and suggest that local angiogenic gene therapy may constitute a novel prevention or treatment for this disorder without augmenting tumor growth or vascularization.

FOXO-dependent expression of the proapoptotic protein Bim: pivotal role for apoptosis signaling in endothelial progenitor cells

Endothelial progenitor cells (EPCs) contribute to postnatal neovascularization. Risk factors for coronary artery disease reduce the number of EPCs in humans. Since EPC apoptosis might be a potential mechanism to regulate the number of EPCs, we investigated the effects of oxidative stress and HMG-CoA-reductase inhibitors (statins) on EPC apoptosis. Atorvastatin, mevastatin, or VEGF prevented EPC apoptosis induced by H2O2. The antiapoptotic effect was reversed by inhibition of the PI3K/Akt pathway. Forkhead transcription factors (FOXO1, FOXO3a, FOXO4) exert proapoptotic effects and are phosphorylated and, thereby, inactivated by Akt. Therefore, we elucidated the involvement of forkhead transcription factors. Atorvastatin induced the phosphorylation of the predominant forkhead factor FOXO4 in EPCs. In addition, atorvastatin reduced the expression of the proapoptotic forkhead-regulated protein Bim in a PI3K-dependent manner. Consistently, overexpression of FOXO4 activated the Bim promoter as determined by reporter gene expression and stimulated the expression of Bim, resulting in an increased EPC apoptosis. Statins failed to prevent EPC apoptosis induced by overexpression of Bim or nonphosphorylatable FOXO4, suggesting that the protective effects of statins depend on this pathway. In summary, our results show that FOXO-dependent expression of Bim plays a pivotal role for EPC apoptosis. Statins reduce oxidative stress-induced EPC apoptosis, inactivate FOXO4, and down-regulate Bim.

Effects of Statins on Endothelium and Endothelial Progenitor Cell Recruitment

Statins appear to be potent drugs with a variety of pleiotropic effects with vasculoprotective and cardioprotective activity. The beneficial effects of statins on endothelial cells as well as on endothelial cell function appear to be related to improved nitric oxide bioavailability. Mechanistically, statins induce endothelial nitric oxide synthase mRNA stability in endothelial cells and promote endothelial nitric oxide synthase activity through a PI3K/Akt dependent pathway, which is a common signal transduction pathway shared by growth factors such as vascular endothelial growth factors or fibroblast growth factors (FGFs), estrogens, or statins. Furthermore, statins have potent antiinflammatory capacities by potently interfering with the generation of reactive oxygen species or activating scavenging systems for free radicals such as the thioredoxin system. These mechanisms might all contribute to improved NO bioavailability and confer the beneficial actions of statins. The proangiogenic properties of statins and their effects on reendothelialization following vessel injury include novel actions such as the mobilization, differentiation, and improved survival of endothelial progenitor cells. Statin therapy might reverse the impaired functional regeneration capacities seen in patients with risk factors for coronary artery disease or documented active coronary artery disease by specifically interacting with progenitor cell function. Accordingly, augmentation of functionally active endothelial progenitor cells with improved homing capacity will be a critical step in advancing therapeutic neovascularization as well as reendothelialization in patients with coronary artery disease.

Secretoneurin, an angiogenic neuropeptide, induces postnatal vasculogenesis

BACKGROUND

Induction of postnatal vasculogenesis, the mobilization of bone marrow-derived endothelial progenitor cells and incorporation of these cells into sites of blood vessel formation, is a well-known feature of angiogenic cytokines such as vascular endothelial growth factor. We hypothesized that the angiogenic neuropeptide secretoneurin induces this kind of neovascularization.

METHODS AND RESULTS

Secretoneurin induced mobilization of endothelial progenitor cells to sites of vasculogenesis in vivo in the cornea neovascularization assay. Progenitor cells were incorporated into vascular structures or were located adjacent to them. Systemic injection of secretoneurin led to increase of circulating stem cells and endothelial progenitor cells. In vitro secretoneurin induced migration, exerted antiapoptotic effects, and increased the number of these cells. Furthermore, secretoneurin stimulated the mitogen-activated protein kinase system, as shown by phosphorylation of extracellular signal-regulated kinase, and activated the protein kinase B/Akt pathway. Activation of mitogen-activated protein kinase was necessary for increase of cell number and migration, whereas Akt seemed to play a role in migration of endothelial progenitor cells.

CONCLUSIONS

These data show that the angiogenic neuropeptide secretoneurin stimulates postnatal vasculogenesis by mobilization, migration, and incorporation of endothelial progenitor cells.

Effects of statins on endothelium and their contribution to neovascularization by mobilization of endothelial progenitor cells

Statins are potent drugs with a variety of cardiovascular protective effects which appear to occur independent of cholesterol reduction. The vasculoprotective effects of statins might be due to their direct effect on endothelial cells leading to improved nitric oxide (NO) bioavailability. Mechanistically, statins induce endothelial nitric oxide synthesis (eNOS) mRNA stability in endothelial cells and promote eNOS activity through a PI3K/Akt dependent pathway. Novel targets of statins are pro-angiogenic actions including the mobilization and differentiation of bone marrow derived endothelial progenitor cells, which accelerate angiogenesis or re-endothelialization. The functional improvement and increased homing capacity of endothelial progenitor cells induced by statin treatment might reverse impaired functional regeneration capacities seen in patients with risk factors for coronary artery disease or documented active coronary artery disease.

Local Gene Transfer of phVEGF-2 Plasmid by Gene-Eluting Stents

Background— Drug-eluting stents represent a useful strategy for the prevention of restenosis using various antiproliferative drugs. These strategies share the liability of impairing endothelial recovery, thereby altering the natural biology of the vessel wall and increasing the associated risk of stent thrombosis. Accordingly, we tested the hypothesis that local delivery via gene-eluting stent of naked plasmid DNA encoding for human vascular endothelial growth factor (VEGF)-2 could achieve similar reductions in neointima formation while accelerating, rather than inhibiting, reendothelialization.

Methods and Results— phVEGF 2-plasmid (100 or 200 μg per stent)–coated BiodivYsio phosphorylcholine polymer stents versus uncoated stents were deployed in a randomized, blinded fashion in iliac arteries of 40 normocholesterolemic and 16 hypercholesterolemic rabbits. Reendothelialization was nearly complete in the VEGF stent group after 10 days and was significantly greater than in control stents (98.7±1% versus 79.0±6%, P <0.01). At 3 months, intravascular ultrasound analysis revealed that lumen cross-sectional area (4.2±0.4 versus 2.27±0.3 mm 2 , P <0.001) was significantly greater and percent cross-sectional narrowing was significantly lower (23.4±6 versus 51.2±10, P <0.001) in VEGF stents compared with control stents implanted in hypercholesterolemic rabbits. Transgene expression was detectable in the vessel wall along with improved functional recovery of stented segments, resulting in a 2.4-fold increase in NO production.

Conclusions— Acceleration of reendothelialization via VEGF-2 gene–eluting stents provides an alternative treatment strategy for the prevention of restenosis. VEGF-2 gene–eluting stents may be considered as a stand-alone or combination therapy.

Profoundly reduced neovascularization capacity of bone marrow mononuclear cells derived from patients with chronic ischemic heart disease

BACKGROUND

Cell therapy with bone marrow-derived stem/progenitor cells is a novel option for improving neovascularization and cardiac function in ischemic heart disease. Circulating endothelial progenitor cells in patients with coronary heart disease are impaired with respect to number and functional activity. However, whether this impairment also extends to bone marrow-derived mononuclear cells (BM-MNCs) in patients with chronic ischemic cardiomyopathy (ICMP) is unclear.

METHODS AND RESULTS

BM-MNCs were isolated from bone marrow aspirates in 18 patients with ICMP (ejection fraction, 38+/-11%) and 8 healthy control subjects (controls). The number of hematopoietic stem/progenitor cells (CD34+/CD133+), CD49d(+) (VLA-4) cells, and CXCR4+ cells did not differ between the 2 groups. However, the colony-forming capacity of BM-MNCs from patients with ICMP was significantly lower compared with BM-MNCs from healthy controls (37.3+/-25.0 versus 113.8+/-70.4 granulocyte-macrophage colony-forming units; P=0.009). Likewise, the migratory response to stromal cell-derived factor 1 (SDF-1) and vascular endothelial growth factor (VEGF) was significantly reduced in BM-MNCs derived from patients with ICMP compared with BM-MNCs from healthy controls (SDF-1, 46.3+/-26.2 versus 108.6+/-40.4 cells/microscopic field, P<0.001; VEGF, 34+/-24.2 versus 54.8+/-29.3 cells/microscopic field, P=0.027). To assess the in vivo relevance of these findings, we tested the functional activity of BM-MNCs to improve neovascularization in a hindlimb animal model using nude mice. Two weeks after ligation of the femoral artery and intravenous injection of 5x10(5) BM-MNCs, laser Doppler-derived relative limb blood flow in mice treated with BM-MNCs from patients with ICMP was significantly lower compared with mice treated with BM-MNCs from healthy controls (0.45+/-0.14 versus 0.68+/-0.15; P<0.001). The in vivo neovascularization capacity of BM-MNCs closely correlated with the in vitro assessment of SDF-1-induced migration (r=0.78; P<0.001) and colony-forming capacity (r=0.74; P<0.001).

CONCLUSIONS

BM-MNCs isolated from patients with ICMP have a significantly reduced migratory and colony-forming activity in vitro and a reduced neovascularization capacity in vivo despite similar content of hematopoietic stem cells. This functional impairment of BM-MNCs from patients with ICMP may limit their therapeutic potential for clinical cell therapy.

Insights Into Early and Rapid Effects of Statin Therapy after Coronary Interventions

Recent trials provide a wealth of data documenting the benefit of cholesterol-lowering therapy with statins in both primary and secondary prevention. A growing body of evidence indicates that statins possess pleiotropic effects - independent of, or at least in addition to their lipid-lowering capacity, including inhibition of smooth muscle cell proliferation and subsequently neointimal proliferation, platelet aggregation as well as antiinflammatory and direct beneficial effects on endothelial function. The current review summarizes recent findings in non-randomized and randomized trials assessing the efficacy of statin therapy following coronary interventions with or without stent implantation. It highlights the efficacy of statins in the settings of acute coronary syndromes. Current management of acute coronary syndromes requires early administration in combination with acute interventions. High risk patients which receive the greatest benefit could be identified by measuring serum markers such as preprocedural C-reactive protein levels. The present article also describes important novel actions of statins supporting the early initiation of statins post intervention, such as the stimulation of reendothelialization - a crucial step in the healing process of the vascular wall - which is mediated at least in part by mobilization of bone-marrow derived endothelial progenitor cells.

[Coronary stent implantation in elderly patients: acute and long-term results]

The number of elderly patients with coronary heart disease is rapidly growing. Morbidity, related with PTCA is increased in elderly patients, presumably because of the more complex adverse baseline characteristics. However, it has not been firmly elucidated whether routine use of coronary stents is associated with a more favourable outcome in this population. Therefore, we investigated the influence of age on acute procedural success, rate of restenosis (quantitative coronary angiography) and major cardiovascular events (death/myocardial infarction [MI]) 6 months after intra-coronary stent implantation in 1306 patients. Patients were categorised into < 65 years (n = 709),65-75 years (n = 443) and >75 years (n= 154).

RESULTS

Older patients had a higher amount of multivessel disease (p < 0.001) and a lower left ventricular ejection fraction (p < 0.001). Nevertheless, the rate of acute success and restenosis were comparable between the different age groups. In contrast, older patients had significantly more adverse clinical events during long-term followup. (Death/MI < 65 years 3.0%, 65-75 years 3.9%, > 75 years 7.8%, p = 0.02). However, by multivariate analysis age was no longer an independent predictor of adverse clinical events (p = 0.26), which were predominantly determined by coexisting impaired left ventricular function (p < 0.001).

CONCLUSION

After proper judgement of the clinical situation, coronary stent implantation should be considered in selected elderly patients. Thus, advanced age as a solely factor should not be regarded as a contraindication for coronary stent implantation.

Endothelial progenitor cells: regulation and contribution to adult neovascularization

BACKGROUND

Recent studies suggest that circulating progenitor cells contribute to the formation of new blood vessels in adults after tissue ischemia. The infusion of these progenitor cells was used as a therapeutic approach to increase vascularization. In several animal models, progenitor cells improved vascularization and capillary density after peripheral or myocardial ischemia. Moreover, transplantation or progenitor cells increased cardiac function after myocardial ischemia. These studies suggest a potential use of progenitor cells for improvement of therapeutic vasculogenesis in patients with ischemic heart disease.

PRESENT STATE

The present article will summarize these findings gained in experimental models. Moreover, novel approaches to increase the function and the number of circulating progenitor cells by pharmacological modulation (cytokines, statins) or gene therapy (VEGF) will be highlighted.

CONCLUSION

Identification of mediators and cellular mechanisms that promote organ-specific recruitment of bone-marrow derived circulating progenitor cells as well as modulation of progenitor cell engraftment will lead to new strategies in order to improve neovascularization and cardiac regeneration in patients with ischemic heart disease.

Statin therapy accelerates reendothelialization: a novel effect involving mobilization and incorporation of bone marrow-derived endothelial progenitor cells

BACKGROUND

Primary and secondary prevention trials suggest that statins possess favorable effects independent of cholesterol reduction. We investigated whether statin therapy may also accelerate reendothelialization after carotid balloon injury.

METHODS AND RESULTS

Simvastatin treatment in 34 male Sprague-Dawley rats accelerated reendothelialization of the balloon-injured arterial segments (reendothelialized area at 2 weeks, 12.3+/-1.8 versus 5.4+/-1.1 mm2, P< 0.01) and resulted in a dose-dependent (0.2 or 1 mg/kg IP) significant reduction in neointimal thickening at 2, 3, and 4 weeks compared with saline-injected controls (n=18). To elucidate the mechanism, we investigated the contribution of bone marrow-derived endothelial progenitor cells (EPCs) by bone marrow transplantation from Tie2/lacZ mice to background mice or nude rats. X-gal staining of mouse carotid artery specimens revealed a 2.9-fold increase in the number of beta-gal-positive cells per square millimeter appearing on the carotid artery luminal surface at 2 weeks, and double-fluorescence immunohistochemistry disclosed a significant 5-fold increase in the number of double-positive cells (beta-gal, isolectin B4) on the luminal surface in carotid arteries of statin-treated nude rats (20+/-3 versus 4+/-1 cells/mm surface length, P<0.005). Statins increased circulating rat EPCs (2.4-fold at 2 weeks and 2.5-fold at 4 weeks, P<0.001) and induced adhesiveness of cultured human EPCs by upregulation of the integrin subunits alpha5, beta1, alpha(v), and beta5 of human EPCs as shown by reverse transcription-polymerase chain reaction and fluorescence-activated cell sorting.

CONCLUSIONS

These findings establish additional mechanisms by which statins may specifically preempt disordered vascular wall pathology and constitute physiological evidence that EPC mobilization represents a functionally relevant consequence of statin therapy.

Benefits of immediate initiation of statin therapy following successful coronary stent implantation in patients with stable and unstable angina pectoris and Q-wave acute myocardial infarction

Statin therapy reduces clinical events in patients with stable coronary artery disease. Recent data indicate that the beneficial effects of statin therapy may also extend to patients experiencing an acute ischemic coronary event. However, the potential role of statins to further modify clinical outcome in patients undergoing coronary stent implantation has not been addressed. Therefore, we investigated whether the initiation of statin therapy immediately after successful coronary stent implantation improves short-term clinical outcome in 704 patients (335 patients with stable angina pectoris [AP], 224 patients with unstable AP, and 145 patients with Q-wave acute myocardial infarction [AMI]). Compared with the lowest risk group (patients with stable AP receiving statin therapy), patients with unstable AP (RR 6.9, 95% confidence interval [CI] 1.5 to 31, p = 0.004) and patients with Q-wave AMI (RR 7.6, 95% CI 1.5 to 37, p = 0.004) experienced an increased risk for the occurrence of the primary combined end point of cardiac death and AMI. Importantly, initiation of statin therapy abrogated the increased risk in patients with unstable AP to the level of patients with stable AP receiving statin therapy (RR 1.5, 95% CI 0.2 to 11, p = 0.7). In contrast, statin therapy did not affect the RR in patients with Q-wave AMI during 6-month follow-up (RR 7.9, 95% CI 1.6 to 39 vs RR 7.6, 95% CI 1.5 to 37, p = NS). The beneficial effects of statin therapy after successful coronary stent implantation in unstable AP were most prominent during the first 4 weeks after the ischemic episode. Statins appear to contribute to the rapid transformation of unstable coronary artery disease into a stable condition with a very low event rate over the forthcoming 6 months in patients with unstable AP undergoing successful coronary stent implantation.

Statin therapy, inflammation and recurrent coronary events in patients following coronary stent implantation

OBJECTIVES

We sought to investigate whether statin therapy affects the association between preprocedural C-reactive protein (CRP) levels and the risk for recurrent coronary events in patients undergoing coronary stent implantation.

BACKGROUND

Low-grade inflammation as detected by elevated CRP levels predicts the risk of recurrent coronary events. The effect of inflammation on coronary risk may be attenuated by statin therapy.

METHODS

We investigated a potential interrelation among statin therapy, serum evidence of inflammation, and the risk for recurrent coronary events in 388 consecutive patients undergoing coronary stent implantation. Patients were grouped according to the median CRP level (0.6 mg/dl) and to the presence of statin therapy.

RESULTS

A primary combined end point event occurred significantly more frequently in patients with elevated CRP levels without statin therapy (RR [relative risk] 2.37, 95% CI [confidence interval] [1.3 to 4.2]). Importantly, in the presence of statin therapy, the RR for recurrent events was significantly reduced in the patients with elevated CRP levels (RR 1.27 [0.7 to 2.1]) to about the same degree as in patients with CRP levels below 0.6 mg/dl and who did not receive statin therapy (RR 1.1 [0.8 to 1.3]).

CONCLUSIONS

Statin therapy significantly attenuates the increased risk for major adverse cardiac events in patients with elevated CRP levels undergoing coronary stent implantation, suggesting that statin therapy interferes with the detrimental effects of inflammation on accelerated atherosclerotic disease progression following coronary stenting.

Allele-specific regulation of matrix metalloproteinase-7 promoter activity is associated with coronary artery luminal dimensions among hypercholesterolemic patients

An enhanced expression of matrix metalloproteinase (MMP)-7 has previously been demonstrated in atherosclerotic and aneurysmal tissue. Because perturbed regulation of MMP-7 may influence the development of these diseases, we searched the MMP-7 promoter for functional polymorphisms. An A to G substitution at position -181 (-181 A/G) and a C to T substitution at position -153 (-153 C/T) with frequencies of 0.50 and 0.10, respectively, were identified. Allele-specific associations were studied in 350 patients undergoing percutaneous transluminal coronary angioplasty. Hypercholesterolemic patients carrying the -181G allele or the -153T allele had smaller reference luminal diameters before percutaneous transluminal coronary angioplasty. Reverse transcription-polymerase chain reaction demonstrated that expression of MMP-7 was confined to differentiated U937 cells. Northern blot analysis could not detect an effect of native or oxidatively modified low density lipoprotein on MMP-7 expression. Thus, the limitation of allele-specific effects on vessel wall remodeling to hypercholesterolemic patients may be secondary to lipid-mediated accumulation of MMP-7-expressing monocyte-derived macrophages within the vessel wall. Both polymorphisms influenced the binding of nuclear proteins. Furthermore, in transient transfection studies, the combination of the 2 rare alleles conferred an increased promoter activity. In conclusion, the present study identified and characterized 2 common polymorphisms in the promoter region of the MMP-7 gene that are functional in vitro and seem to influence coronary arterial dimensions in hypercholesterolemic patients with manifest coronary artery disease.

Proposed quality control guidelines for National Committee for Clinical Laboratory Standards Susceptibility Tests using the veterinary antimicrobial agent tiamulin

Quality control guidelines for standardized antimicrobial susceptibility test methods are critical for the continuing accuracy of these clinical tests. In this report, quality control limits were proposed for the veterinary antimicrobial agent tiamulin with minimum inhibitory concentration (MIC) ranges of three or four log(2) dilution steps in two different medium formulations. Disk diffusion zone diameter ranges were proposed for tiamulin tested against Actinobacillus pleuropneumoniae ATCC 27090 (12-18 mm) and Staphylococcus aureus ATCC 25923 (25-32 mm). The data from eight participating laboratories produced 100% of results within proposed MIC limits (8-32 microg/mL), and 95.8-97.0% of zones were found within suggested zone diameter QC guidelines. These proposed QC ranges should be validated by in-use results from veterinary clinical laboratories.

Reversal of experimental diabetic neuropathy by VEGF gene transfer

The pathogenetic basis for diabetic neuropathy has been enigmatic. Using two different animal models of diabetes, we have investigated the hypothesis that experimental diabetic neuropathy results from destruction of the vasa nervorum and can be reversed by administration of an angiogenic growth factor. Nerve blood flow, as measured by laser Doppler imaging or direct detection of a locally administered fluorescent lectin analogue, was markedly attenuated in rats with streptozotocin-induced diabetes, consistent with a profound reduction in the number of vessels observed. A severe peripheral neuropathy developed in parallel, characterized by significant slowing of motor and sensory nerve conduction velocities, compared with nondiabetic control animals. In contrast, 4 weeks after intramuscular gene transfer of plasmid DNA encoding VEGF-1 or VEGF-2, vascularity and blood flow in the nerves of treated animals were similar to those of nondiabetic control rats; constitutive overexpression of both transgenes resulted in restoration of large and small fiber peripheral nerve function. Similar experiments performed in a rabbit model of alloxan-induced diabetes produced comparable results. These findings support the notion that diabetic neuropathy results from microvascular ischemia involving the vasa nervorum and suggest the feasibility of a novel treatment strategy for patients in whom peripheral neuropathy constitutes a secondary complication of diabetes.

Statin therapy is associated with reduced restenosis rates after coronary stent implantation in carriers of the Pl(A2)allele of the platelet glycoprotein IIIa gene

Aims Platelets play a central role in the restenosis process by inducing neointimal proliferation after coronary interventions. Glycoprotein IIb/IIIa Pl(A2)polymorphism has been associated with the occurrence of acute coronary syndromes and increased restenosis rates. Statins have been shown to exert potent antiproliferative, antiinflammatory and antithrombotic properties, thereby potentially interfering with the major processes of in-stent restenosis. Therefore, we sought to find out whether statin therapy interferes with restenosis and clinical outcome at 6 months following successful coronary stent implantation in the presence or absence of the Pl(A2)allele. Methods and Results Six hundred and fifty consecutive patients were followed for 6 months after coronary stent insertion. Carriers of the Pl(A2)allele demonstrated a significantly increased restenosis rate, which was abrogated by statin therapy (50.9% vs 28.6%, P=0.01). Moreover, statin therapy was associated with a significant reduction (28.2% vs 49.3%, P<0.01) in the occurrence of major adverse coronary events (myocardial infarction, cardiac death, target vessel revascularization) in the 6 months after the intervention in patients with the Pl(A2)allele. Conclusion Statin therapy reduces increased stent restenosis rates and improves clinical outcome following coronary stent implantation in patients bearing the Pl(A2)allele, suggesting that statins interfere with the functional consequence of a genetically determined platelet-mediated risk factor associated with Pl(A2)polymorphism.

Preprocedural C-reactive protein levels and cardiovascular events after coronary stent implantation

OBJECTIVES

This study assessed the predictive value of preprocedural C-reactive protein (CRP) levels on six-month clinical and angiographic outcome in patients undergoing coronary stent implantation.

BACKGROUND

Recent data indicate that low-grade inflammation as detected by elevated CRP serum levels predicts the risk of recurrent coronary events.

METHODS

We prospectively investigated the predictive value of preprocedural CRP-levels on restenosis and six-month clinical outcome in 276 patients after coronary stent implantation. The primary combined end point was death due to cardiac causes, myocardial infarction related to the target vessel and repeat intervention of the stented vessel.

RESULTS

Grouping patients into tertiles according to preprocedural CRP-levels revealed that, despite identical angiographic and clinical characteristics at baseline and after stent implantation, a primary end point event occurred in 24 (26%) patients of the lowest tertile, in 42 (45.6%) of the middle tertile and in 38 (41.3%) of the highest CRP tertile, p = 0.01. On multivariate analysis, tertiles of CRP levels were independently associated with a higher risk of adverse coronary events (relative risk = 2.0 [1.1 to 3.5], tertile I vs. II and III, p = 0.01) in addition to the minimal lumen diameter after stent (p = 0.04). In addition, restenosis rates were significantly higher in the two upper tertiles compared with CRP levels in the lowest tertile (45.5% vs. 38.3% vs. 18.5%, respectively, p = 0.002).

CONCLUSIONS

Low-grade inflammation as evidenced by elevated preprocedural serum CRP-levels is an independent predictor of adverse outcome after coronary stent implantation, suggesting that a systemically detectable inflammatory activity is associated with proliferative responses within successfully implanted stents.

Treatment of aortocoronary vein graft lesions with membrane-covered stents: A multicenter surveillance trial

BACKGROUND

Stent implantation in lesions of degenerated aortocoronary vein grafts is associated with a high risk of periprocedural thrombus embolization and in-stent restenosis.

METHODS AND RESULTS

In a multicenter study, we followed up 109 consecutive patients (mean age 66+/-8 years, 12% female) who received polytetrafluoroethylene (PTFE) membrane-covered stents for 125 de novo stenoses in vein grafts 11+/-5 years after bypass surgery. Stent deployment was successful in all but 1 patient; 1 patient suffered from subacute stent thrombosis. Six-month cardiac mortality was 7% (8 patients), 3 patients (3%) underwent repeat bypass surgery, and 9 patients (8%) required target-lesion PTCA. Repeat angiography revealed vessel occlusions in 9% and in-stent restenosis in 8% of patients by the end of follow-up.

CONCLUSIONS

Membrane-covered stents appear to be a safe and efficient treatment strategy associated with a low incidence of restenosis and target-vessel revascularization. Compared with previous studies, the investigated device is not associated with an increase in mortality or late vessel occlusions.

Laminar shear stress upregulates integrin expression: role in endothelial cell adhesion and apoptosis

Laminar shear stress exerts important effects on endothelial cell (EC) function and inhibits apoptosis of ECs induced by various stimuli. The mechanism by which hemodynamic forces, such as shear stress, are transduced into cellular signaling is still not known. Located at the cell surface, integrins, which are required for cell adhesion and cell survival, are potential mechanotransducers. Therefore, we investigated the effect of shear stress on integrin expression in ECs. Shear stress time-dependently increased the mRNA expression of the fibronectin receptor subunits alpha(5) and beta(1) with a maximum at 6 hours (283+/-41% and 215+/-27% of control, respectively). In addition, the protein levels of the fibronectin receptor subunits alpha(5) and beta(1) were enhanced with a maximum at 12 hours of shear stress exposure (343+/-53% and 212+/-38% of control, respectively). The shear stress-induced upregulation of integrins is independent of nitric oxide. Furthermore, we confirmed the enhanced functional activity of alpha(5)beta(1) integrin expression by FACS analysis. As a functional consequence, human umbilical vein ECs, which were preexposed to shear stress, revealed a significantly increased attachment (178+/-10% of static controls) and a more pronounced extracellular signal-regulated kinase 1 and 2 activation in response to cell attachment. Finally, we demonstrated that shear stress requires RGD-sensitive integrins to mediate its antiapoptotic effect. Taken together, these results define a novel mechanism by which shear stress may exert its atheroprotective effects via upregulation of integrins to support EC adhesion and survival.

Elevated C-reactive protein levels and impaired endothelial vasoreactivity in patients with coronary artery disease

BACKGROUND

Elevated C-reactive protein (CRP) serum levels, an exquisitely sensitive objective marker of inflammation, relate to long-term prognosis in patients with coronary artery disease and in apparently healthy men. Because abnormalities of endothelial regulation of vascular function may contribute to the occurrence of coronary events, we tested the hypothesis that elevated CRP levels are associated with an abnormal systemic endothelial vascular reactivity.

METHODS AND RESULTS

Endothelium-dependent (10 to 50 microg/min acetylcholine) and endothelium-independent (2 to 8 microg/min sodium nitroprusside) forearm blood flow responses were measured with venous occlusion plethysmography in 60 male patients with angiographically documented coronary artery disease. Forearm blood flow responses to acetylcholine were inversely correlated with CRP serum levels (r=-0.46, P:=0.001). With multivariate analysis that included the classic risk factors for coronary artery disease, elevated CRP serum level remained a statistically significant independent predictor of a blunted endothelial vasodilator capacity. Most important, normalization of elevated CRP levels over time was associated with a normalization of endothelium-mediated forearm blood flow responses after 3 months.

CONCLUSIONS

Thus, elevated CRP serum levels indicative of a systemic inflammatory response are associated with a blunted systemic endothelial vasodilator function. The identification of elevated CRP levels as a transient independent risk factor for endothelial dysfunction might provide an important clue to link a systemic marker of inflammation to atherosclerotic disease progression.

Allele-specific regulation of matrix metalloproteinase-12 gene activity is associated with coronary artery luminal dimensions in diabetic patients with manifest coronary artery disease

Both the processes of atherosclerosis and plaque rupture are indicated to be influenced by matrix metalloproteinase (MMP) activity. We therefore searched for common functional variation in the matrix metalloelastase (MMP-12) gene locus that may be implicated in coronary artery disease. Single-strand conformation polymorphism analysis of DNA from healthy individuals detected a common polymorphism within the MMP-12 gene promoter (an A-to-G substitution at position -82). The frequency of the G allele was 0. 19. The polymorphism influences the binding of the transcription factor activator protein-1 (AP-1) in electromobility shift assay. A higher binding affinity of AP-1 to the A allele was associated with higher MMP-12 promoter activity in vitro in transient transfection studies in U937 and murine lung macrophage (MALU) cells. Phorbol 12-myristate 13-acetate (PMA) and insulin, 2 known activators of AP-1, increased the binding of AP-1 to the MMP-12 promoter, with higher affinity for the A allele. In transfection experiments, both the A and the G alleles responded to insulin and PMA, the A allele showing higher promoter activity than the G allele. Furthermore, Western blot analysis demonstrated that insulin increased MMP-12 protein production. To analyze whether the -82 A/G polymorphism is associated with coronary artery disease, 367 consecutive patients who underwent percutaneous transluminal coronary angiography with stent implantation were genotyped. In patients (n=71) with diabetes, the A allele was associated with a smaller luminal diameter. In conclusion, a common functional polymorphism within the MMP-12 promoter influences coronary artery luminal dimensions in diabetic patients with manifest coronary artery disease.

Effect of statin therapy on restenosis after coronary stent implantation

The effect of statins on the development of restenosis and clinical outcome after coronary stent implantation was assessed in a retrospective analysis of 525 consecutive patients. Baseline clinical, angiographic, and procedural characteristics did not differ between 258 patients with and 267 patients without statin therapy. Statin therapy was associated with a significantly (p<0.04) improved survival free of myocardial infarction and a significant reduction in repeat target vessel revascularization procedures (27.9% vs. 36.7%, p<0.05) during 6-month follow-up. Minimal lumen diameter was significantly larger (1.98+/-0.88 vs. 1.78+/-0.88 mm, p = 0.01), late lumen loss was significantly less (0.64+/-0.8 vs. 0.8+/-0.8 mm, p = 0.032), and net gain significantly increased (1.2+/-0.88 vs. 0.98+/- 0.92 mm, p = 0. 009) in patients receiving statin therapy. Dichotomous angiographic restenosis (> or =50%) rates were significantly lower, with 25.4% in the statin group compared with 38% in the no-statin group (p<0.005). Multivariate analysis identified statin therapy (p = 0.005), minimal lumen diameter immediately after stenting (p = 0.02), and stent length (p = 0.02) as independent predictors for subsequent restenosis development. Thus, statin therapy is associated with reduced recurrence rates and improved clinical outcome after coronary stent implantation.

[Genetic risk factors for myocardial infarct]

Interactions of genetic and environmental risk factors influence the susceptibility to coronary artery disease (CAD) and myocardial infarction. In myocardial infarction occurring at young age, genetics of this multifactorial disease may be the leading factor. A number of candidate genes have been implicated in the pathogenesis of CAD and myocardial infarction. Mutations in the DNA sequence (gene polymorphisms) have been identified that appear to play a crucial role in blood pressure regulation, lipid metabolism, endothelial function, in the pathophysiology of coagulation or thrombosis, or in interventional cardiology by interfering with restenosis development. Genetic polymorphisms seem to be clinically important because they not only potentiate the individual risk under certain circumstances, but they also determine safety and effectiveness of commonly prescribed drugs. Understanding the complexity and functional relevance of genetic risk factors will be useful in early detection and treatment of individuals that are exposed to higher risk for myocardial infarction. Thus it is important to include genetic risk factors in the concept of the classical risk factor theory. Potentially in future a genetic risk profile including relevant polymorphisms may be an essential part of the clinicians' knowledge in primary and secondary prevention of coronary artery disease.

A positive family history of premature coronary artery disease is associated with impaired endothelium-dependent coronary blood flow regulation

BACKGROUND

The aim of the study was to determine whether a positive family history of coronary artery disease is related to impaired coronary blood flow regulation.

METHODS AND RESULTS

In 150 patients with angiographically normal or minimally diseased coronary vessels, risk factors for coronary artery disease, the extent of atherosclerosis and endothelium-dependent vasomotor responses to acetylcholine, and endothelium-independent blood flow regulation by papaverine or adenosine were assessed. Coronary blood flow responses to acetylcholine were reduced in a dose-dependent manner in patients with a positive family history (P=0.030). By multivariate analysis, hypercholesterolemia (P=0.001), age (P=0.002), and a positive family history (P=0.008) remained predictors of coronary blood flow increase to acetylcholine. The extent of atherosclerotic coronary artery disease was, by multivariate analysis, an additional independent predictor of acetylcholine-induced blood flow (P=0.014), but also of endothelium-independent blood flow regulation (P=0.001). A positive family history had additive effects in addition to the other risk factors, such as hypercholesterolemia or increased age. Angiotensin-converting-enzyme genotype polymorphism had no influence either on endothelium-dependent or endothelium-independent coronary blood flow responses. However, in a subset of 28 patients, homocysteine (which is, in part, genetically determined) was inversely related to maximal acetylcholine-induced blood flow regulation (r=-0.47, P=0.012).

CONCLUSIONS

The results of this study demonstrate, for the first time, that a positive family history of coronary artery disease is an important predictor of impaired endothelium-dependent coronary blood flow regulation in humans. The influence of a positive family history is independent of other well known risk factors but instead aggravates endothelial vasodilator dysfunction associated with hypercholesterolemia and increased age, suggesting important interacting effects between genetic and environmental risk factors.

Coronary stent grafts covered by a polytetrafluoroethylene membrane

In a prospective observational study, 40 patients were treated with coronary stent grafts covered by a polytetrafluoroethylene membrane. These devices may be regarded as therapy of choice for acute coronary rupture; treatment of conventional in-stent restenosis was not associated with a favorable outcome, whereas the promising results in degenerated vein grafts warrant a randomized, controlled trial.

Cyclosporin A inhibits apoptosis of human endothelial cells by preventing release of cytochrome C from mitochondria

BACKGROUND

Several experimental and clinical studies suggest that cyclosporin A (CSA) treatment reduces transplant atherosclerosis. Because oxidized LDL (oxLDL) is believed to play a key role in the development of atherogenesis, causing injury to the endothelium, and has been shown to induce apoptosis of endothelial cells, we investigated whether CSA inhibits oxLDL-induced apoptosis.

METHODS AND RESULTS

Apoptosis was induced in human umbilical venous endothelial cells (HUVECs) by incubation of 10 microg/mL oxLDL for 18 hours. Coincubation with CSA dose dependently decreased oxLDL-induced apoptosis, with a maximal effect at 10 micromol/L. In addition, tumor necrosis factor-alpha- and angiotensin II-induced apoptosis was significantly prevented by CSA treatment, suggesting a general apoptosis-suppressive effect of CSA. CSA has been shown to inhibit disruption of the mitochondrial membrane function, which plays a key role in apoptosis induction. Indeed, oxLDL treatment triggered the release of cytochrome C from the mitochondria into the cytosol, indicating disturbance of the mitochondrial membrane. CSA (10 micromol/L) completely inhibited the oxLDL-induced release of cytochrome C. Moreover, tumor necrosis factor-alpha- and angiotensin II-induced cytochrome C release was prevented by CSA treatment.

CONCLUSIONS

OxLDL induces dysfunction of the mitochondrial membrane, leading to cytochrome C release into the cytosol, and thereby stimulates apoptosis of human endothelial cells. Apoptosis suppression by CSA correlates with the prevention of mitochondrial dysfunction and thus indicates the importance of mitochondrial destabilization in oxLDL-induced apoptosis signaling. The inhibition of apoptosis by CSA might preserve the function of the endothelium and may at least in part contribute to the antiatherogenic effects of CSA in transplant atherosclerosis.

Platelet glycoprotein IIIa polymorphisms and risk of coronary stent thrombosis

BACKGROUND

Coronary stents are an effective treatment for selected coronary stenoses. However, thrombosis of the stented segment is a major adverse complication. Platelet aggregation has a key role in stent thrombosis. We investigated whether a polymorphism of platelet glycoprotein IIIa gene (PIA2) is associated with an increased risk of coronary stent thrombosis.

METHODS

318 consecutive patients were followed up for 30 days after coronary stent insertion. The primary endpoints were death, myocardial infarction, stent-vessel occlusion, and coronary artery bypass surgery. Gel electrophoresis of PCR products was used to identify the PIA1 and PIA2 alleles. The relative risk of stent occlusion was calculated from the odds ratio on logistic regression analysis.

FINDINGS

63 (19.8%) of patients had the PIA2 allele and 255 (80.2%) were homozygous for PIA1. Baseline clinical, angiographic, and procedural features did not differ between the groups with and without the PIA2 allele. Occlusion of the stent vessel occurred in five (1.9%) patients homozygous for PIA1 and six (9.5%) patients with PIA2 allele (odds ratio 5.26 [95% CI 1.55-17.85]). On multivariate regression analysis PIA1/A2 genotype was the only significant independent predictor of stent thrombosis.

INTERPRETATION

Patients with the pIA2 allele have an increased risk of coronary stent thrombosis, which may warrant antiplatelet therapy with glycoprotein-IIb/IIIa inhibitors, although bleeding complications may also increase.

Endoscopic microsurgical dissection of the esophagus (EMDE)

This paper presents endoscopic microsurgical dissection of the esophagus (EMDE), a surgical technique for the therapy of esophageal cancer which improves blunt esophageal dissection with the aim of reducing postoperative morbidity and mortality. A mediastinoscope with integrated operative instrument channel, fibre bundles, optic and rinsing channel has been developed whereby precise and atraumatic esophageal dissection is possible via a cervical access incision. Between 1989 and 1993, 37 patients were operated on using the EMDE technique and are compared with 48 patients operated on during the same period by the thoraco-abdominal route. The operative duration was reduced by the new technique, and although the number of severe complications was not significantly different between both groups, the rate of pulmonary and cardiac complications was reduced. The mortality rate was 10% for EMDE patients and 14% for the thoraco-abdominal procedure, and there was no difference in the long-term survival rate. As distinct from procedures requiring a thoracotomy for esophageal dissection, EMDE permits ventilation of both lungs throughout the entire operation and reduces the total operative trauma.

VEGF improves myocardial blood flow but produces EDRF-mediated hypotension in porcine hearts

Several recent studies have demonstrated the potential for improving myocardial perfusion by the continuous administration of angiogenic growth factors. Studies in our laboratory have shown that a single intraarterial or intravenous bolus of the endothelial cell specific mitogen vascular endothelial growth factor (VEGF) can significantly improve perfusion in a rabbit ischemic limb model. To test the efficacy of this therapeutic approach in chronic myocardial ischemia, 18 Yorkshire pigs underwent a left thoracotomy followed by placement of an ameroid constrictor around the proximal circumflex coronary artery. Gradual occlusion of the artery (26 +/- 4 days) was accompanied by identifiable hypokinesis of the posterolateral wall of the left ventricle (2D echo). Thirty days postoperatively, rhVEGF(165) (2 mg; n = 8) or saline (n = 10) was administered directly into the left coronary ostium. Postadenosine myocardial perfusion studies using colored microspheres 30 days later demonstrated superior blood flow in the ischemic zone of the VEGF-treated hearts (ischemic/normal ratio 1.09 vs 0.97, P < 0.05) compared with those receiving saline injection. Four of eight VEGF-treated animals succumbed, however, to severe hypotension following VEGF administration. Therefore 500 micrograms of VEGF were administered intracoronary to five normal pigs. A significant drop in mean arterial pressure (-44.4 +/- 3.2%, P < 0.05 vs baseline) and peripheral resistance (-13.2 +/- 4.5%, P < 0.05 vs baseline) was accompanied by increased heart rate. IV administration of N(omega)-nitro-L-arginine (L-NNA), an EDRF inhibitor, restored blood pressure to baseline. We conclude that a single intracoronary bolus of VEGF is capable of significantly augmenting flow to collateral-dependent ischemic myocardium. The associated hypotension appears to be EDRF-mediated. Further studies are needed to define the best dose and route of administration of VEGF for the treatment of coronary insufficiency.

The in vivo bioactivity of vascular endothelial growth factor/vascular permeability factor is independent of N-linked glycosylation

The carbohydrate moieties of glycoprotein hormones or growth factor molecules may have a variety of effects that impact biological potency. Vascular endothelial growth factor (VEGF), also known as vascular permeability factor (VPF), is a 45 kD heparin-binding, endothelial cell (EC) specific mitogen with a putative N-linked glycosylation site. Recent studies have shown that VEGF/VPF may successfully augment collateral development in animal models of myocardial and hindlimb ischemia. The extent to which glycosylation of the 75 asparagine site affects the angiogenic properties of VEGF/VPF has not been studied in vivo. Specifically unaddressed to date is the concern that nonglycosylated VEGF/VPF may be less stable, and therefore characterized by a shorter half-life, reducing its utility for therapeutic angiogenesis. Accordingly, the purpose of this study was to investigate the extent to which posttranslational modification, specifically glycosylation, mofies the angiogenic properties of VEGF/VPF in vivo. Glycosylated (g+) recombinant human VEGF165 was purified from media conditioned by Chinese hamster ovary (CHO) cells. Nonglycosylated (g-) VEGF165 was expressed, purified and refolded from E. coli. The purity of both materials was assessed by silver-stained SDS/PAGE and characterized by the presence of a single amino terminal sequence as indicated by Edman degradation. Tryptic mapping by reverse-phase HPLC confirmed that the potential glycosylation site at 75 asparagine was occupied by N-linked carbohydrate for the Chinese hamster ovary-derived VEGF/VPF, but not for E. coli-derived VEGF/VPF. The mitogenic effects of Chinese hamster ovary-derived (g+) VEGF165 and E. coli-derived (g-) VEGF165 wre studied in vitro using microvascular EC. At concentrations of VEGF/VPF ranging from 10(-4) to 10(2) nM, both produced similar concentration-dependent effects on EC proliferation. For in vivo studies, (g-) (n = 8) and (g+) (n = 8) formulations of VEGF/VPF were administered to New Zealand white rabbits with unilateral hindlimb ischemia. For (g-) versus (g+) VEGF/VPF-treated groups, respectively, calf blood pressure ratio was 0.40 +/- 0.04 versus 0.37 +/- 0.04; angiographic score (of collateral vessels) was 0.37 +/- 0.04 versus 0.35 +/- 0.04; capillary density (capillaries/mm2) at necropsy was 246.9 +/- 21.5 versus 253.9 +/- 18.8; and tissue perfusion (colored microspheres) was 92.8 +/- 5.5 versus 90.30 +/- 13.47 (all p = ns). Moreover, intravascular Doppler-based analyses of resting, maximum, and endothelium-dependent flow was similar for (g-) and (g+) VEGF/VPF. These in vitro and in vivo findings establish that the potential for VEGF/VPF to stimulate therapeutic angiogenesis persists unaltered in the nonglycosylated state.